Electromagnetic counter

ABSTRACT

An electromagnetic counter for digitally counting applied signal pulse numbers, including resetting mechanism for simultaneously resetting a series of digit wheels to their zero position. Actuating force for the resetting mechanism is applied to a rockable first lever, which has the same number of resetting arms as that of the digit wheels for rotating them to zero position and a lever arm for rotating a rotatable frame supporting a series of pinions engaged between each of the digit wheels into pinions&#39;&#39; disengaging position. There is provided between the lever arm of the first lever and the rotatable frame a second lever pivoted at its respective ends to them for transmitting the actuating force. The pivoting point of the first lever, respective pivoting points between the first and second levers and the second lever and rotatable pinion frame are substantially aligned on a straight line so as to make repulsing torque given to the pinions from the digit wheels to be small.

United States Patent Hara et al. Mar. 7, 1972 [54] ELECTROMAGNETIC COUNTER 3,053,441 9/1962 Vroom ..235/l44 UX [72] Inventors: Kazuhiko Ham; Hiram lmai both of 3,321,134 5/1967 Sigl ..235/ 144 HC Kadoma Osaka Japan Primary Examiner-Maynard R. Wilbur [73] Assignee: Matsushita Denko Kabushiki Kaisha, Assistant Examiner-Joseph M. Thesz, Jr.

Osaka, Japan Att0rneyWolfe, Hubbard, Leydig, Voit & Osann, Ltd.

[22] Filed: Nov. 24, 1969 57] ABSTRACT [2]] Appl' 879m) An electroma netic counter for di itall countin a lied 8 B Y 8 PP signal pulse numbers, including resetting mechanism for [30] Foreign Application Priority Data simultaneously resetting a series of digit wheels to their zero I position. Actuating force for the resetting mechanism is apg g2 i f plied to a rockable first lever, which has the same number of 1968 12827 resetting arms as that of the digit wheels for rotating them to apan zero position and a lever arm for rotating a rotatable frame 52 us. Cl... .....23s/92 c, 235/92 R, 235/144 HC 9 PQ' f each [51] [m Cl G06m 1/30 digit wheels into pimons disengaging positlon. There IS pro- [58 1 Fie'ld 5/ 1 44 HC vided between the lever arm of the first lever and the rotatable frame a second lever pivoted at its respective ends to them for transmitting the actuating force. The pivoting point of the first [56] References Cited lever, respective pivoting points between the first and second UNITED STATES PATENTS levers and the second lever and rotatable pinion frame are substantially aligned on a straight line so as to make repulsmg g l h torque given to the pinions from the digit wheels to be small. a ze 2,980,329 4/1961 Hoffmann ..235/ 144 UX 4 Claims, 26 Drawing Figures Patented March 7, 1972 6 Sheets-Sheet l RM n O E TA N NHA R w M o O T mK T I A W2 0 Am KH Patented March 7, 1972 6 Sheets-Sheet 2 m m m w M 0 mm m w o Am KH Patented March 7, 1972 3,648,028

6 Sheets-Shoot 4 F/g. 6A

INVENTORS KAZUl-HKO HARA" HIROZO IMAI b .'4/,,M%,M+@M

ATTO R NEY3 Patented March 7, 1972 3,648,028

6 Sheets-Shoot 5 INVENTORS KAZUHIKO HARA Hmozo [MAI Patented March 7, 1972 6 Sheets-Shoot 6 INVENTORS KAZUHIKO HARA Hmozo IMAI AFTORNEYS ELECTROMAGNETIC COUNTER This invention relates to electromagnetic counters.

In conventional electromagnetic counters of the kind, there have been such defects that, in the case when letter or digit wheels would be subsequently rotated through pinions during the accumulative counting operation, the pinions would have to receive a repulsing force from gearwheels fixed to the respective digit wheels the sum of this repulsing force and a force of pinion removing springs would be apt to become larger than a force of resetting spring employed for resetting the digit wheels to their zero point and, thereby, the pinions would become readily disengageable with the gears fixed to the digit wheels, consequently so called miscounting would be caused to occur.

The present invention has been suggested to remove these defects as above. According to the present invention, problems causing these defects have been effectively solved by providing, in the electromagnetic counter wherein the digit wheels are rotated by means of attractive action of an armature or armatures attracted by excited electromagnet or electromagnets, a second lever as interposed between a first driving lever and a rotary frame for pinions and so arranging respective pivoting points between the rotary frame and the second lever and between the first and second levers and bearing point of the first lever as to be aligned substantially on a straight line so that the pinions will become hard to misengage with the digit wheels even with the repulsing force given to the pinions for position shift from the digit wheels.

Further according the present invention, it is enabled to make the force of resetting springs for resetting a pushbutton to their original position small and, thus, automatic resetting of them by means of a resetting electromagnet is made to be easier, so that the electromagnet will be made smaller and as a whole the electromagnetic counter will be minimized in dimension.

Yet further according to the present invention, it is made possible to make clearance between the digit wheels and the driving and resetting electromagnets smaller by positioning an operating mechanism for causing the digit wheels to show zero points. Therefore, longitudinal size of the electromagnetic counter to be smaller and hence required space for mounting the counter can be made also smaller.

According to the present invention, further, anchor arm length can be made shorter so as to reduce given load to the driving electromagnet. Therefore, high-speed characteristics of the counter will be able to be much improved.

According to the present invention, furthermore, a resilient force required for resetting the anchor in order to rotate the digit wheels and another resilient force for resetting the pushbutton are able to be provided by a single-resetting spring. Thus, the number of parts of the counter can be made smaller as compared with conventional counters, so that the structure of the counter will become simpler and, consequently, assembling operation will become easier.

It is a further feature of the present invention that a transparent plate formed integrally with a lenz portion is mounted to an outer frame member as engaged with its both end edges and, therefore, a separate lens member will not have to be mounted to the outer frame and, thus, a separate strengthening member is not required for bridging between the both end edges of the frame. For these reasons required working operation for setting any measuring mechanism inside the frame will become easier, stiffness of the frame will be sufficiently strengthened by the transparent plate, and there is no such fear that the mounting of the lenz will be loosened.

As another feature of the present invention, terminal base member will be positively fixed to the frame simply by inserting the same into cutoff portion of the frame so as to coat the frame within inside surface of a case. Therefore, assembling and diassembling operations are remarkably simplified, replacing operation ofthe terminal base member is made easier, and the terminal base members become allowable mutually exchanged.

Other features and advantages of the present invention will become clear as the following disclosures proceed with reference to the accompanying drawings, in which:

FIGS. lA'and 1B are perspective views of acase or housing of the electromagnetic counter employed in the present invention.

FIGS. 2A and 2B are perspective views of the electromagnetic counter of the invention as assembled in the case shown in FIG. 1.

FIGS. 3A through 3F show a lower side plan view, a front side view, a rear side view, a right side view, upper side plan view, and a left side view of the counter with the case removed, respectively.

FIG. 4 is a perspective view of the counter shown in FIG. 3 as disassembled. I

FIG. 5 is a plan view of digit wheel unit in the counter of the present invention.

FIGS. 6A through 6C are left side, front side and right side views of one of the digit wheels.

FIGS. 7A through 7C are similar views ofa pinion to FIG. 6.

FIGS. 8A and 8B show resetting mechanism of the digit wheels in a perspective view.

FIG. 9 shows an explanatory view of mounting state of terminals. v

FIG. 10 is an explanatory view to show the operation of the counter of the invention.

FIGS. 11A and 11B are explanatory views to show resetting operation for the digit wheels. I

FIG. 12A shows schematically the operation of the counter according to the present invention, and FIG. 128 shows similarly the operation ofconventional counters.

While the present invention shall be explained in detail with reference to an embodiment of the counter as depicted in the drawings, it is not intended to limit the invention to the particular embodiment but is rather intended to include all possible alterations, modifications and equivalent arrangements to be included in the spirit and scope of the invention as recited in the appended claims.

Referring now to FIG. 1, 1 is a case for housing therein the electromagnetic counter assembly. The case 1 is provided at is reverse side with an opening 2 and with windows 3 and 3 for locking the counter assembly to the case, as seen in FIG. 18, and at its front side with a slit 4 for allowing a resetting pushbutton to be projected out of the case and with a digit viewer window 5, as seen in FIG. 1A.

As shown in FIG. 2A, a pushbutton 6 for resetting a plurality of digit wheels 7 aligned inside the viewer window 5 to their zero positions will extrude at the front side of the case I. At the rear side of the case, terminals 8 for driving electromagnet, terminals 9 for resetting electromagnet, and rear sidewall of a frame 10 including fixing screws 11 are exposed from the case, and projections 12 and 12' for locking the frame 10 to the case 1 are engaged in the respective windows 3 and 3', as shown in FIG. 2B.

In FIGS. 3A through 3F, 13 is a driving electromagnet and 14 rotatably a resetting electromagnet, both of which are fixed to the rear sidewall of the frame 10 by means of the fixing screws ll. 15 and 16 are a T-shaped plate spring, respectively, which are fixed at their vertical ends to the body of the electromagnets l4 and 15, respectively. Each of the other free end lateral arms of the springs 15 and I6 is engaged with an end of respective driving armature l7 and resetting armature 18. The armature I7 is to be driven by magnetic attraction of the driving electromagnet I3 with the engaged end with the T-shape spring 15 as a fulcrum. The other free end of the armature l7 enters in a recess 38 (see FIG. 4) of an anchor member 19 which is rotatablly supported by an axis 37 (see FIG. 4) penetrating through the frame 10. Ratchet nails 20 and 20' are provided on the anchor 19 are brought into an engagement with a gearwheel 21. As the armature I7 is driven, the ratchet nails 20 and 20 of the anchor 19 will be caused to effect a rocking movement by the armature 17 through the recess 38, with which movement the gearwheel 21 is made to be rotated.

This rotation will be transmitted through a pinion gear unit 22 to the digit wheels 7. Each of the digit wheels 7 and the pinion gears 22 are arranged in such manner that a rotation of one of the wheels 7 will be transmitted to an adjacent one of them subsequently through each adjacent one of the pinion gears 22. 23 is a rotary frame for supporting the pinion gears 22 with a shaft 102 (see FIG. The frame 23 is in turn supported on the frame rotatably around a shaft 105 (see FIG. 4). 24 is a first lever rotatably mounted on a shaft 94 supported on the frame 10, for driving a heart-shape cam 28 (see FIGS. 11A and 11B). 26 is a resetting spring. 27 is a pinion stopper member, which is adapted to prevent the rotary frame 23 from being rotated and also to correct the arrangement of the pinions 22.

Turning now to FIG. 4, all of the component parts of the counter is to be contained as assembled in the frame 10. The frame 10 is formed substantially in a U-shape and is provided, at its sidewalls 29 and 29, with the projections 12 and 12 and holes 30 of various sizes, at its open end side edges, with cutouts 31 and 31' and, at its rear sidewall, with holes 32, The driving electromagnet 13 comprises a yoke 33 of an L-shape, a core 34 inserted in a coil bobbin 35, a coil 36 wound on the bobbin 35, and the driving armature 17 held against an end edge of said yoke 33 movably by means of the T-shape plate spring 15. The driving electromagnet 13 thus formed will be fixed to the frame 10 by means of the fixing screw 11 as screwed into bottom end of the core 34 through one of the holes 32 in the rear sidewall of the frame 10 and a hole made in rear end wall of the yoke 33. The resetting electromagnet 14 is formed and fixed to the frame 10 substantially in the same structure and manner as in the case of the above, except that the armature 18 has a different structure at its operative free end from that of the driving armature 17.

The anchor member 19 is mounted rotatably on the first s shaft 37 which is fixed at its both ends to each ofthe both walls 29 and 29' of the frame 10, and is provided with the recess 38 for receiving operative free end of the driving armature 17 and with the ratchet nails for providing rotary feed action to the gearwheel 21 for driving the digit wheels 7, as referred to before. 26 is a resetting spring, which is wound on the fixed shaft 37 and engaged at an end with a projection 39 formed at a longitudinal end of the anchor 19 and at the other end with a projection 40 formed likely at a longitudinal end of the heart cam driving first lever 24.

The gearwheel 21 comprises a star wheel section 41 to be driven by the ratchet nails 20 of the anchor 19 and a driving gear section 42 as joined together. The gear 21 is rotatably mounted on a second fixed shaft 43 fixed at both ends to the respective walls 29 and 29' ofthe frame 10.

Each of a plurality of the digit wheels 7, which is shown in FIG. 5 with reference numerals 44 through 49 for detailed explanation following, has a digit representation of0 through 9" on its periphery. The wheels 44 through 49 are provided on a side surface with follower gears 50 through 55, respectively, and on the other side surface with driver gears 56 through 61, respectively. Further on either ones of these follower and driver gears, the digit wheels 44 through 49 are provided with heart-shaped earns 62 through 67, respectively, which are shown in the present instance to be formed on a side surface of the follower gears 50 through 55. These digit wheels are rotatably mounted on the second fixed shaft 43 in a subsequent arrangement, and the gearwheel 21 is likely mounted on the same shaft 43 with its driving gear 42 as opposed to the heart-shape cam 62 of the first digit wheel 44 (see FIG. 5). As seen in FIG. 6 which showing details of, as an example, the digit wheel 44, while the follower gear 50 has 20 teeth therearound, the driver gear 56 has merely two teeth on its side surface. This is for the reason that, in order to transmit onctenth rotation ofa right-hand digit wheel in the illustrated arrangement to a left-hand digit wheel, that is, to make such an intermittent transmission to be effective, it is sufficient in the function to utilize only two teeth at the left side surface of the right hand Wheel and to remove other eighteen teeth. It

should be also noted here that the heart-shape cam 62 is shown to be mounted on the side of the follower gear 50 for convenience, but the same may be positioned on the other side as desired.

The pinion gears 22 comprise in the present instance a similar subsequent arrangement of first pinion 68 through sixth pinion 73, as seen in FIG. 5. In FIG. 7, there are shown details of an exemplary one of the first pinion 68. Each of the pinions is provided with a follower gear, labeled as 74 in FIG. 7, at a side of its disc-shape body and with a driver gear. labeled as 80, at the other side. The driver gear has eight teeth of the respectively same height, while the follower gear 74 has eight teeth comprising four higher teeth and four lower teeth respectively alternately arranged.

The subsequent series of pinions 68 through 73 are mounted rotatably on a third shaft 102 fixed at its both ends on the rotary frame 23, and are employed to effect so-called position shift action for the digits represented by the series of digit wheels 7. For this purpose, the pinions 68 through 73 are provided, as referred to in the above, with the follower gears 74 through 79 and the driver gears 80 through 85, respectively. The digits position shift will be established with a linkage interconnection between the gearwheel 2l-pinion 68digit wheel 44-pinion 69--digit wheel 45pinion 70digit wheel 46pinion 71digit wheel 47-pinion 72-digit wheel 48 pinion 73-digit wheel 49 through the respective ones of driver and follower gears. Now, when the ratchets 20 of the anchor member 19 is actuated to rotate the star wheel 41 of the gearwheel 21, the driver gear 42 will drive its associated follower gear 74 of the first pinion 68, the driver gear 80 of this pinion 68 will in turn drive its associated follower gear 50 of the first digit wheel 44, the driver gear 56 of this wheel 44 will in turn intermittently drive its associated follower gear 75 of the second pinion 69, the driver gear 81 of this pinion 69 will in turn drive its associated follower gear 63 of the second digit wheel 45, and the same driving and following actions are transmitted to adjacent pinions and digit wheels, while effecting the transmissions of one-tenth rotation of the first digit wheel to the second digit wheel, one-tenth rotation of the second digit wheel to the third digit wheel, and so on.

The resetting mechanism for the digit wheels shall now be explained in the following.

Referring to FIG. 8, the pushbutton 6 for actuating the resetting mechanism is provided at its inside forward end with a hole 86 and at its intermediate portion with a long hole 87 for allowing the shaft 43 bearing the digit wheels 44 through 49 to pass freely therethrough. The heart-cam driving first lever 24 is provided along its main body with a plurality of arms 88 (corresponding number to that of the digit wheels) formed vertically to the body and in parallel relation to each other as spaced by a regular distance. Each of the respective arms 88 is provided at its forward end with a hook portion 89 for engaging each of the heart-shape cams. The lever 24 is also provided at one side ofits main body with a sidewall 90 including a pin 91 for engaging the pushbutton 6 through a later discussed second lever 98, a projection 40 for bearing an end of the resetting spring 26, and a hole 93. At the other side of the body, the lever 24 is also provided with a boss 95 having a hole 96, and a fourth shaft 94 fixed at both ends to the frame 10 will be passed through these holes 93 and 96. Further, there is provided adjacent the sidewall 90 an engaging groove 97 for receiving free end of the resetting armature 18.

The before mentioned second lever 98 has at an end a hole 99 and at the other end a long hole 100. The pin 91 at the sidewall 90 of the first lever 24 will be inserted through the hole 99 into the hole 86 of the pushbutton 6, so that the button 6 and the first and second levers 24 and 98 are connected with each other in rotatable manner. In the long hole 100, a pin 101 provided at an end of the rotary frame 23 will be inserted. The rotary frame 23 supports the series of pinions 22 in a rotatable manner with a third shaft 102, which is fixed at both ends to the frame 23 as inserted in its holes 104. 103 is a hole made in both arms of the frame 23 between the hole 104 and the pin 101, and receives a fifth shaft 105 fixed at its both ends to the respective sidewalls 29 and 29, of the frame 10, so that the rotary frame 23 will be supported by the frame in a rotatable manner with respect to the walls 29 and 29. A coil spring 106 will be mounted around the fifth shaft 105 so as to be engaged at an end 107 with an edge of the rotary frame 23 and at the other end 108 with an edge of the stopper 27 coupled to the sidewalls 29 and 29 of the frame 10, thereby the rotary frame 23 will be urged in a direction shown by an arrow A in FIG. 8A, that is, in the direction in which the pinions 22 will be disengaged from the digit wheels 7.

Referring again to FIG. 4, 109 is a transparent viewer plate having at the center a lens section 110 extending in the longitudinal direction, at respective side edges projections 111, at one of the edges a cutout 112, and adjacent the other edge a slit 113 for exposing the pushbutton 6 out of the plate 109. Said projections 111 will be engaged in the respective cutouts 31 and 31' at both ends of the frame 10, so that when the sidewalls 29 and 29 are inserted in the case 1 the lens 110 will exposed out of the case 1 through its window 5 (see FIG. 2).

Referring next to FIG. 9, the terminals 8 are fixedly held in a terminal base 114 made of an electrically insulative material, which having at both ends stepped edges 115 and at the center a vertical through hole 116. Each of the terminals 8 will be fixed as penetrated through the base 111 at the position between the hole 116 and the respective stepped edges 115. In the U-shaped frame 10, there are provided a pair of cutouts 117 and 118 so as to form therebetween a projection 119, so that the latter will be inserted in the vertical through hole 116 of the base member 114 and, thus, the base 114 will be fixed to the frame 10. Inner surface of the housing case 1 will be butted against outside face of thus fixed base 114.

The operation of the electromagnetic counter according to the present invention shall now be explained.

During the time when there are no electric pulse current is applied to the terminals 8 and 9, the lever 24 for driving the heart-shape cams in the series of digit wheels 7 is not engaging the heart-shape cams as being biased by the resetting spring 26 and, therefore, the series of pinions 22 are brought into an engagement with the follower and driver gears of the series of digit wheels 7, respectively. Now, as the pulse current is applied to the terminals 8, the driving electromagnet 13 will be excited so as to attract the driving armature 17, thereby the anchor 19 associated with the armature 17 at the recess 38 will be rotated about the first shaft 37 as a center in the direction of an arrow D as shown in FIG. 10. Then, one of the ratchet nails 20 of the anchor 19 at the farthest side to the armature 17 will be brought into engagement with the star wheel 41 of the gear 21 and push the same into a rotation in the same direction, which rotation will be transmitted to the digit wheel 44 through associated pinion 68, so that numbers of applied pulses will be represented by the digits on the digit wheels.

In order to reset the digit wheels to their zero position, a pulse current may be applied to the terminals 9 for actuating the resetting electromagnet 14, or the resetting pushbutton 6 may be manually pushed in the direction of an arrow E shown in FIG. 11. Details of this resetting operation shall now be explained with reference to FIGS. 11A and 118.

When the pushbutton 6 is pushed in the direction E:

i. As the first lever 24 and the intermediate second lever 98 are connected with each other through the pin 91 in rotatable relation to each other, the arms 88 of the lever 24 will be rotated about the shaft 94 as a center in the direction of an arrow B, so that the first one of the arms 88, for example, will engage the first heart-shape cam 62.

ii, At the same time, the second lever 98 will be drawn in the direction of an arrow C, so that the pin 101 of the rotary frame 23 engaged in the hole 100 of the lever 98 will be also drawn in the same direction C. Then, together with resilient force of the spring 106 given to the frame 23 all the time, the lever 98 will rotate the frame 23 in the direction A about the fifth shaft 105 as a center, so that the series of pinions 22 will be separated from the follower and driving gears of the digit wheels 7.

iii. At the same time when the pinions 22 are separated from the gears of digit wheels, the heart-shape cam 62 will be pressed by hook portion 89 of the arms 88 of lever 24 so as to be rotated in the direction B up to the position where the center 62 of the cam 62 will engage the hook 89, so that the digit wheels and their associated follower and driver gears will be simultaneously rotated until the wheels will show zero digits through the window 5 of the case 1 at the said position of the cam 62 as shown in FIG. 118. It should be noted that, since the above resetting action is to be effected equally to all of the digit wheels, the digits of all the digit wheels can be simultaneously returned to 0" When the pushing force is released from the pushbutton 6:

iv. The lever 24 will be returned to its original position as urged by biasing force of the spring 26 so as to turn back the pushbutton 6.

A remarkable advantage of the above structure brought about according to the present invention resides in the fact that the pinions are not easily disengageable from the gears of digit wheels during the normal counting operation. The reason for this fact shall now be explained with reference to FIGS. 12A and 128.

Reference shall be first made to FIG. 12A showing the counting operation of the counter according to the present invention, in which:

1. Bearing force that the pinions shaft receives from associated gears during the accumulative counting operation (which force acts as a repulsion force) shall be represented by N.

2. When the force added by the repulsion force N in a direction passing through the long hole of intermediate second lever 98 and axial line of the pin 91 is represented by F there will be established a relation Consequently, as will be seen from the above equations, the smaller (Tn 5; will be, the smaller M becomes. Therefore,'the first lever 24 will become hard to rotate, and the value of P can be made smaller.

In other words, even when a considerably large repulsion force N is applied to the pinion, the heart cam driving first lever 24 will not be moved, so that the pinions and associated gears will be always retained in their normal positions.

When 0 m 0, the structure will be in such that the pinions will never disengage the associated gears at all and, therefore, the resetting spring 26 may be made extremely small.

In conventional structures, an exemplary one of which being shown in FIG. 128, the heart cam driving lever 88 is pivoted at a shaft 5 to a rotary frame 23'. P shows resilient biasing force of a resetting spring 26'. In this instance, a rear portion is butted at it point m against an extended part of the rotary frame 23.

Now in such arrangement: 1. The repulsion force that the pinions receive from their associated gears shall be represented by N. 2. When the additional force applied to the heart cam lever 88' due to the repulsion force N is represented by F,, the same will be 3. Then, rotational torque M applied to the heart cam lever 88' due to the repulsion force N will be re resented by M,=F, 5,M,=N Therefore, since the torque M due to the repulsion force N -will be directly applied to the heart cam lever 88', it arises gDl then, the pinions would have to be separated away from the digit wheels. Therefore, even when the repulsion force N is negligiblly small, the return biasing force P will be required to exist.

To the contrary, in the structure according to the present invention, as has been described in the foregoing, it is enabled to make the rotational torque M to be small as much as desired by making the distance O m and, for this reason, the biasing force P can be likely made small as much as desired.

We claim:

1. An electromagnetic counter comprising a plurality of rotatable number wheels each having a gear for driving the respective wheels and a plurality of pinions each associated with one of the number wheel gears for driving the number wheels, a resetting mechanism comprising the combination of a frame member carrying said pinions and mounted on a fixed pivot shaft for pivotal movement to move said pinions into and out of engagement with the number wheel gears, a plurality of heart-shaped cams fixed to one of said number wheels, a lever mounted on a fixed pivot shaft for pivotal movement into and out of engagement with said heart-shaped cams, a lever pivotally connected to said first lever and to said frame member, said pinions being mounted on said frame member on one side of the pivot point of said frame member and said second lever being pivotally connected to said frame member on the other side of said pivot point, said frame member, said first lever and said second lever being arranged so that l s ai d fixed pivot point of said first lever, (2) the point of pivotal connection between said first lever and said second lever, and (3) the point of pivotal connection between said second lever and said frame member, lie substantially on a straight line whereby forces tending to urge said pinions away from the number wheel gears are resisted by the fixed pivot shaft of said first lever via said first and second levers and said frame member.

2. An electromagnetic counter as set forth in claim 1 which includes means for driving said number wheels comprising a rotatable armature, an electromagnetic device for advancing said armature, an anchor member mounted for pivotal movement in response to movement of said armature, said anchor member being mounted on an elongated pivot shaft, a coil spring wound around said shaft with one end of the spring engaging said anchor member and the other end of said spring engaging said first lever whereby said spring urges said anchor member toward its retracted position and the same spring urges said first lever away from said heart-shaped cams.

3. An electromagnetic counter as set forth in claim I which includes means for driving said number wheels comprising a rotatable armature, an electromagnet device for advancing said armature, an anchor member mounted for pivotal movement in response to movement of said armature, said anchor member being mounted on an elongated pivot shaft, a U- shaped frame member having its bottom portion fixed to the bottom of said electromagnet device with said anchor member, said number wheels, said first lever, and said frame member being mounted between the sidewalls of said U- shaped frame member via shafts fixed at both ends to said sidewalls, a transparent plate bridging the open ends of said sidewalls, a housing having an open end for receiving said U- shaped frame member and a closed end including viewer win dows for said number wheels when said transparent plate is butted against said closed end.

4. An electromagnetic counter as set forth in claim 3 wherein said Ushaped frame member is provided at one edge of the bottom thereof with at least two cutouts to form a projection substantially at the center of said edge, and including a base member forming a hole for receiving said projection, said base member including terminal pieces having one end exposed outside said U-shaped frame member and the other end enclosed within said U-shaped frame member for connection to said electromagnetic device. 

1. An electromagnetic counter comprising a plurality of rotatable number wheels each having a gear for driving the respective wheels and a plurality of pinions each associated with one of the number wheel gears for driving the number wheels, a resetting mechanism comprising the combination of a frame member carrying said pinions and mounted on a fixed pivot shaft for pivotal movement to move said pinions into and out of engagement with the number wheel gears, a plurality of heart-shaped cams fixed to one of said number wheels, a lever mounted on a fixed pivot shaft for pivotal movement into and out of engagement with said heart-shaped cams, a lever pivotally connected to said first lever and to said frame member, said pinions being mounted on said frame member on one side of the pivot point of said frame member and said second lever being pivotally connected to said frame member on the other side of said pivot point, said frame member, said first lever and said second lever being arranged so that (1) said fixed pivot point of said first lever, (2) the point of pivotal connection between said first lever and said second lever, and (3) the point of pivotal connection between said second lever and said frame member, lie substantially on a straight line whereby forces tending to urge said pinions away from the number wheel gears are resisted by the fixed pivot shaft of said first lever via said first and second levers and said frame member.
 2. An electromagnetic counter as set forth in claim 1 which includes means for driving said number wheels comprising a rotatable armature, an electromagnetic device for advancing said armature, an anchor member mounted for pivotal movement in response to movement of said armature, said anchor member being mounted on an elongated pivot shaft, a coil spring wound around said shaft with one end of the spring engaging said anchor member and the other end of said spring engaging said first lever whereby said spring urges said anchor member toward its retracted position and the same spring urges said first lever away from said heart-shaped cams.
 3. An electromagnetic counter as set forth in claim 1 which includes means for driving said number wheels comprising a rotatable armature, an electromagnet device for advancing said armature, an anchor member mounted for pivotal movement in response to movement of said armature, said anchor member being mounted on an elongated pivot shaft, a U-shaped frame member having its bottom portion fixed to the bottom of said electromagnet device with said anchor member, said number wheels, said first lever, and said frame member being mounted between the sidewalls of said U-shaped frame member via shafts fixed at both ends to said sidewalls, a transparent plate bridging the open ends of said sidewalls, a housing having an open end for receiving said U-shaped frame member and a closed end including viewer windows for said number wheels when said transparent plate is butted against said closed end.
 4. An electromagnetic counter as set forth in claim 3 wherein said U-shaped frame member is provided at one edge of the bottom thereof with at least two cutouts to form a projection substantially at the center of said edge, and including a base member forming a hole for receiving said projection, said base member including terminal pieces having one end exposed outside said U-shaped frame member and the other end enclosed within said U-shaped frame member for connection to said electromagnetic device. 